Re: OOM problems with 2.6.11-rc4

[Andrew Morton]

Andrea Arcangeli <andrea@xxxxxxx> wrote:
>
> This below is an untested attempt at bringing dquot a bit more in line
>  with the API, to make the whole thing a bit more consistent,

Like this?  (Noah, don't bother testing this one)



Fix some bugs spotted by Andrea Arcangeli <andrea@xxxxxxx>

- When we added /proc/sys/vm/vfs_cache_pressure we forgot to allow it to
  tune the dquot and mbcache slabs as well.

- Reduce lock contention in shrink_dqcache_memory().

- Use dqstats.free_dquots in shrink_dqcache_memory(): this is the count of
  reclaimable objects.

Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---

 25-akpm/fs/dquot.c   |   12 +++++-------
 25-akpm/fs/mbcache.c |    2 +-
 2 files changed, 6 insertions(+), 8 deletions(-)

diff -puN fs/dquot.c~slab-shrinkers-use-vfs_cache_pressure fs/dquot.c
--- 25/fs/dquot.c~slab-shrinkers-use-vfs_cache_pressure	2005-03-16 04:22:01.000000000 -0800
+++ 25-akpm/fs/dquot.c	2005-03-16 04:27:09.000000000 -0800
@@ -505,14 +505,12 @@ static void prune_dqcache(int count)
 
 static int shrink_dqcache_memory(int nr, unsigned int gfp_mask)
 {
-	int ret;
-
-	spin_lock(&dq_list_lock);
-	if (nr)
+	if (nr) {
+		spin_lock(&dq_list_lock);
 		prune_dqcache(nr);
-	ret = dqstats.allocated_dquots;
-	spin_unlock(&dq_list_lock);
-	return ret;
+		spin_unlock(&dq_list_lock);
+	}
+	return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
 }
 
 /*
diff -puN fs/mbcache.c~slab-shrinkers-use-vfs_cache_pressure fs/mbcache.c
--- 25/fs/mbcache.c~slab-shrinkers-use-vfs_cache_pressure	2005-03-16 04:22:01.000000000 -0800
+++ 25-akpm/fs/mbcache.c	2005-03-16 04:24:43.000000000 -0800
@@ -225,7 +225,7 @@ mb_cache_shrink_fn(int nr_to_scan, unsig
 						   e_lru_list), gfp_mask);
 	}
 out:
-	return count;
+	return (count / 100) * sysctl_vfs_cache_pressure;
 }
 
 
_

-
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